Current silver halide film cameras have displays for indicating settings and status conditions, such as frame number, of the camera. Often, the display uses twisted nematic liquid crystals that that requires continuous electrical drive to display information. Cameras with this type of display are usually turned on only for short periods of time to preserve battery life. When the cameras are turned off, the liquid crystal display goes blank. An operator must turn on the camera to determine the status of the camera. These cameras typically incorporate a high voltage supply to drive an electronic flash built into the camera, and utilize cartridges that contain the film in a light tight environment.
Many digital cameras use liquid crystal displays to display a captured image. Displays in these cameras are also nematic liquid crystals displays that can drain an electronic camera power supply in a short period of time.
Many digital cameras also use removable memory cards to store images. There is no way to tell how much capacity remains or what images reside on these memory cards without turning the camera on.